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Related to groined: grained

groin 1

1. Anatomy The crease or hollow at the junction of the inner part of each thigh with the trunk, together with the adjacent region and often including the external genitals.
2. Architecture The curved edge at the junction of two intersecting vaults.
tr.v. groined, groin·ing, groins
To provide or build with groins.

[Alteration (influenced by loin) of Middle English grinde, perhaps from Old English grynde, abyss, hollow.]

groin 2

A small jetty extending from a shore to protect a beach against erosion or to trap shifting sands.

[Early Modern English groyne, ultimately (via Middle French groin, snout, promontory, headland, and Middle English groin, snout) from Old French groin, snout, promontory, from Late Latin grunium, snout, from Vulgar Latin *grunīre, to grunt, variant of Latin grunnīre, to grunt.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
References in classic literature ?
In the middle of this groined and vaulted public square was an oaken table which they called the Table Round.
The room into which they entered was a vaulted chamber once nobly ornamented by cunning architects, and still retaining, in its beautiful groined roof and rich stone tracery, choice remnants of its ancient splendour.
But, as I stood under the blackened, groined arches of that old synagogue, made dimly visible by the seven thin candles in the sacred lamp, while our Jewish cicerone reached down the Book of the Law, and read to us in its ancient tongue--I felt a shuddering impression that this strange building, with its shrunken lights, this surviving withered remnant of medieval Judaism, was of a piece with my vision.